Red Hat Enterprise Linux 8 update for kernel-rt
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 3 |
| CVE-ID | CVE-2021-22543 CVE-2021-22555 CVE-2021-3609 |
| CWE-ID | CWE-119 CWE-787 CWE-362 |
| Exploitation vector | Local |
| Public exploit |
Public exploit code for vulnerability #1 is available. Vulnerability #2 is being exploited in the wild. Public exploit code for vulnerability #3 is available. |
| Vulnerable software Subscribe |
Red Hat Enterprise Linux for Real Time - Telecommunications Update Service Operating systems & Components / Operating system Red Hat Enterprise Linux for Real Time for NFV Operating systems & Components / Operating system Red Hat Enterprise Linux for Real Time Operating systems & Components / Operating system kernel-rt (Red Hat package) Operating systems & Components / Operating system package or component |
| Vendor | Red Hat Inc. |
Security Bulletin
This security bulletin contains information about 3 vulnerabilities.
1) Buffer overflow
EUVDB-ID: #VU56018
Risk: Low
CVSSv3.1: 7 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]
CVE-ID: CVE-2021-22543
CWE-ID:
CWE-119 - Memory corruption
Exploit availability: Yes
DescriptionThe vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error in Linux kernel when handling VM_IO|VM_PFNMAP vmas in KVM. A local user can can bypass RO checks and cause the pages to get freed while still accessible by the VMM and guest. As a result, an attacker with the ability to start and control a VM to read/write random pages of memory, can trigger memory corruption and execute arbitrary code with elevated privileges.
Install updates from vendor's website.
Red Hat Enterprise Linux for Real Time - Telecommunications Update Service: 8.4
Red Hat Enterprise Linux for Real Time for NFV: 8
Red Hat Enterprise Linux for Real Time: 8
kernel-rt (Red Hat package): before 4.18.0-305.12.1.rt7.84.el8_4
CPE2.3- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time_-_telecommunications_update_service:8.4:*:*:*:*:*:*:
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time_for_nfv:8:*:*:*:*:red_hat_enterprise_linux:*:
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time:8:*:*:*:*:red_hat_enterprise_linux:*:
http://access.redhat.com/errata/RHSA-2021:3088
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.
2) Out-of-bounds write
EUVDB-ID: #VU56017
Risk: Low
CVSSv3.1: 7.5 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]
CVE-ID: CVE-2021-22555
CWE-ID:
CWE-787 - Out-of-bounds write
Exploit availability: Yes
Description The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error when processing untrusted input in net/netfilter/x_tables.c in Linux kernel. A local user can run a specially crafted program to trigger an out-of-bounds write and execute arbitrary code with elevated privileges.
Install updates from vendor's website.
Red Hat Enterprise Linux for Real Time - Telecommunications Update Service: 8.4
Red Hat Enterprise Linux for Real Time for NFV: 8
Red Hat Enterprise Linux for Real Time: 8
kernel-rt (Red Hat package): before 4.18.0-305.12.1.rt7.84.el8_4
CPE2.3- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time_-_telecommunications_update_service:8.4:*:*:*:*:*:*:
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time_for_nfv:8:*:*:*:*:red_hat_enterprise_linux:*:
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time:8:*:*:*:*:red_hat_enterprise_linux:*:
http://access.redhat.com/errata/RHSA-2021:3088
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
Yes. This vulnerability is being exploited in the wild.
3) Race condition
EUVDB-ID: #VU54292
Risk: Medium
CVSSv3.1: 7.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]
CVE-ID: CVE-2021-3609
Exploit availability: No
DescriptionThe vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a race condition in the CAN BCM networking protocol (net/can/bcm.c) in the Linux kernel ranging from version 2.6.25 to mainline 5.13-rc6. A local user can exploit the race and gain unauthorized access to sensitive information and escalate privileges on the system.
MitigationInstall updates from vendor's website.
Red Hat Enterprise Linux for Real Time - Telecommunications Update Service: 8.4
Red Hat Enterprise Linux for Real Time for NFV: 8
Red Hat Enterprise Linux for Real Time: 8
kernel-rt (Red Hat package): before 4.18.0-305.12.1.rt7.84.el8_4
CPE2.3- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time_-_telecommunications_update_service:8.4:*:*:*:*:*:*:
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time_for_nfv:8:*:*:*:*:red_hat_enterprise_linux:*:
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_real_time:8:*:*:*:*:red_hat_enterprise_linux:*:
http://access.redhat.com/errata/RHSA-2021:3088
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.
